RemoteDesktop ($12.99 after trial) is a full RDP Remote Desktop client for connecting to Professional editions (those that support including connections) of Windows XP, Vista, 7 and 2003 Server. It natively connects via RDP, and it doesn't require an extra server component, unless the computer isn't available on the Internet. If connecting locally, you can use the server component. RemoteDesktop supports standard security or Network Level Authentication (NLA). Multiple resolutions and pinch zoom are also supported.

8. SimpleVNC

SimpleVNC ($0.99 after trial) is another remote desktop client, but it supports the platform-independent VNC protocol. You can use it to connect to and control a Windows, Mac or Linux machine. The computer just has to have a VNC server (such as the free TightVNC or UltraVNC) installed.

9. Mobile SQL

Mobile SQL ($5.99) can connect to a Microsoft SQL server or Oracle MySQL database. You can then run queries and updates directly from your phone. It's a simple application that is great for performing occasional or emergency maintenance tasks.

10. VPSinn

VPSinn (Free) lets you access, manage and monitor your virtual environment. It's compatible with the Citrix XenServer and Xen Cloud Platform (XCP). You can check the status of your virtual machines, view their properties, and change states (e.g., start, stop, suspend, reboot and live migration).

11. My FTP

My FTP ($1.29) is an FTP client with DropBox support. Connect to Internet-accessible FTP or NAS servers or your DropBox account to access, upload, download and manage your files. Its integrated file support lets you see images, play movies, listen to music and open text files.

12. SubCalc Subnet Calculator

SubCalc Subnet Calculator (Free) helps you calculate the network address, wildcard mask, subnet mask and other IP info. This is great when deploying a new network or configuring existing network components. You can input an IP address, define the number of hosts needed and the prefix length. It will then display the subnet and wildcard mask and broadcast address.